Brake



March 1933- G. A. HALFVARSON BRAKE 2 Sheets-Sheet 1 Filed April 12, 1928 -------Gu$/zy A.//a/fmrson.

March 21, 1933.

G. A. HAL vA oN BRAKE Sheets-Shet 2 Filed April 12-, 1928 ATl'ORNEY rammed Mar. 21, 1933 UNITED STATE-1S- P TE T oFF I cE Gus'rAF A. HALFVARsQN, F VEBOKA, rmmsYLv niA, ASSIGNOR, rownsirilmrroqsia a ELECTRIC & MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA BRAKE App ca i n l d Apr 12,

My invention relates to improvements in brakes and particularly to brake mechanism of the eleotro-mechanical type in which the brake is applied mechanicallyby springs or their equivalents and is released by an electromagnet or motor; The object ofstated, is the provision of a brake that shall be simple and efficient in operation, readily adjustable and adapted for easy and economical manufacture. I

A more specific object of my inventionis v to provide a brake in which no lost motion u occurs during the operation of its movable parts. I

Another object'of my invention is to provide a brake in which the brake'shoes areself-aligning in all directions on the brake drum. I It is also an object of my invention to provide a brake that maybe operated with a minimum amount of clearance'betw'een the brake shoes and the brake drum.

Other objects of the invention will, in part,

be obvious and-will,'in part, appear hereinafter. V For an illustration of one of the various forms my invention may take, reference may be had tothe accompanying drawingsiin which'; Figure 1 is a view, in end elevation, of a brake embodyingm'y inventiony i Y Fig. 2 is a view, in side elevatiomof the brake illustrated in Fig. 1; and

V Fig. 3 is a view, in section,taken along the 7 line 'IIIIII of Fig. 1. 1 p In the drawings, Ihave illustrated a brake drum 1 as aflixed to a driving shaft 2 to whicha braking effect is to be applied. 'Surrounding the brake drum 1 is a yoke or frame 3-,.

which carries and supports a pair-of brake levers 4 and 5 andan electromagnet 6 for operating the brake levers. r

As shown, the brake levers 4 and 5 are disposed on opposite sides ofthe drum'l with their lower ends pivotally connected by pivot pins 7 and 8 to the frame 3 and are provided with a pair of brake shoes 9 and 10. for engagingthe brake .drum 1.-

' It will be noted that each of brakehe invention, generally 192s. seriai no. 269,535. r

shoes Qand 10 is seated on its'supporting brake lever by means of a universal joint in the iorm of a ball-and-socket connection comprising a ball'12 formed on the shoe and a socket 13 formed inthe central portion of the lever. Each shoe is bolted to its supporting lever by means of an eye bolt 15, the'inner end of which is secured in a slot'l6 in the ball portion of the shoe by pivot pin 17.! As shown, the inner end of the eye bolt 15 is mounted onthep'ivot pin 17 in the shoe with.

sufiicient play to permit the shoe to rotate, I

between the shoes and the drum, the shoes Will be accurately aligned with the drumthe firsttime they are applied thereto by-the brake, regardless of the'degree to which the eyebolts may be'tightened, and, by reason of the frictional engagement of the balls in the sockets, will retain theirfalignment when I they are withdrawn from the drum. Inasy much as the shoes are held tightly against the levers by the eye bolts under all conditions, no lost motion can occur between the shoes and the levers. l a

The means for applying the brake shoes 9 and 10 to the brake drum 1 comprises a pair of compression springs 20 and 21 which are mounted on the outer ends of a pair. of eye bolts 22 and 23 in position to press against the uppere'ndsof the brakeljevers 4 and 5, The inner ends of theeyejbolts 22 and 23 are 's'ecured to the frame'3 by a pair ofipivot pins 24 and 25, and the outer ends are provided I justed.

The electromagnet 6 for releasing the:

brake shoes is mounted on the upper central portion'of the frame 3 and is suitably conwith. a pair of nuts 26 and 27 by which th tension of the springs20' and 2l'may' beadnected to the brake levers 4 and-5 to-separate them. against the. force ofthe springs 20 and 21. As shown, electr omagnet 6 is provided x the outer ends im in e a ainst the inner I I 1 ends of a pair of set screws 35 and 36 in the brake levers 4 and 5 and thus act as a means for separating the brake levers when the electromagnet 6 is energized. Each of the set screws 35 and 36 is provided with a locking nut 37 for retaining it in anyposition to which it may be adjusted.

, The clearance between the brake shoes 9 and 10 and the brake drum 1 when the brake levers 4 and 5 are separated by the eleetroa magnet 6 may be'adjusted by loosening the locking nuts 37-and rotating the set screws 35 and 36 in the proper direction. a

It-will be observed that the brake mecha nism is arranged in such manner that all of the forces exerted by the brake shoes 9 and 10 and, by the electromagnet 6 are directed against the inner sides of the brake levers 4 and 5 at points between the pivotal supports of the levers and the compression springs 20 and 21 and, therefore, that the forces exerted by'the springs keep the lower ends of the levers-pressed against the inner sides of the pivot pins? and 8 at'all times; 5 I r Viith the brake arranged in the manner described,no lostmotio-n can occur in the movement'of the various parts during the operation of the brake, and, therefore,the brake can, be adjusted with a: minimum amount of clearance between the drum and the shoes I Also, forces that tend to deflect the lever 4 act in the same direction when-the brake is 9 applied or released, and therefore there is no effect of lost motion,;d ue to deflection'of the arm 4; under the influence of pressure of the spring 20 or'the lever 32.

V In the operation of the brake mechanism, the brake shoes 9' and 10 are normally held in engagement with the brake drum 1 by thecompression springs 20 and 21. ,Assuming that it is desired to release the brake drum 1, then the conductors 38' and '39 I leading to the electromagnet 6 are connectedto asuitthe electromagnet. The energization of the electromagnet causes its armature 31 to move downwardly against the inner ends ofthe bell-crank levers 32 and 32 and actuatethem to separate the brake levers l and 5against the action of the springs 20 and21, thereby releasing the brake shoes 9 and 10 from the brake'drum 1. l v 1 It will, therefore, be understood that I have devised a brake that is exceedingly quick in action b-yreason of the fact that no lost motion occurs in theoperation o f-lits mova= ble parts and that is provided with shoes which are self-aligning in all directions;

It will also be observed that the brake shoes 9 and 10 are operated independently of each other and, therefore, that any defect in one shoe will not affect the operation shoe.

ofthe other While the illustrated example constitutes a particular embodiment of my invention, 1 do not limit myself structurally to the details shown, since, manifestly, the same maybe varied considerably without departing from the splrit of the invention as defined inthe appended claims. v

" I claim as my invention: 9 1. A brake comprising a brake drum, 'a

frame associated with said drum, a pairof brake levers pivotally, mounted, at their lower ends,'on saidflfralliafa pair of brake shoes disposed on the inner centraljportions pluralityv of springs independently mounted on said frame, and engaging the upper ends of said levers for engaging said drum, a

of saidlevers for actuating said levers independently into braking position, and ire: leasing means positioned for engaging said brake levers'between the brake shoes and the springs.

2'. la -brake comprising, a brake drum,

a pair of brake levers, a pair of brake shoes, an adjustable universal joint for supporting one of the brake shoes on the inner central portion 10f each of said brake levers for engaging said brake drum, means for continuously biasing'said brake levers toward the brake drum, and releasing means "for hold-- lng thebrake levers 1n brake-releasing posi:: ,tion 1n opposltlon to said biaslng means and so disposed that the levers are always strained in the same direction whether the brake is released or applied, whereby no lost motion can occur in the operation of thelevers. 1 3.'A brake, comprising abrakedrum, a

frame associated with said drum, brake levers pivotally mounted, at their lower ends, on said frame, a pair of brake shoes, adjustable universal mountings for supporting one of sald brake shoes on each of said levers for engaging said-drum, a plurality of springs independently mounted'on said frame and .r en a in the u er ends of said leversfor able sourceof electrical energy to energlze' b g pp actuating said levers independently into braklng position, and means for releasing said brake levers, said releasing means and said brake'shoes being connected to the in ner faces of the c brake levers intermediate thelr ends, whereby the levers will always be stralned in the same direction whether the '4. In a brake-mechanismya brake drum;

a pivoted brakelever having a semil spheri cal bearing socket, a brake shoe having a s herical bearing member seated in said soc et for movement therein to permit all portions of the contact face of said shoe to engage said drum when said shoe is moved into contact therewith by said lever, an eye bolt extending axially through said socket and bearing member, a pivot pin extending laterally through said bearing member and the eye of said bolt, and a nut on the outer end of said eye bolt for drawing the bearing member tightly into said socket member thereby causing the brake shoe to be frictionally retained in a proper position for ac- V curately engaging said brake drum.

In testimony whereof, I have hereunto subscribed my name this 10th day of April 1928.

GUSTAF A. HALFVARSON, 

